The present invention relates to a work platform for attachment to a helicopter. In particular, a platform is adapted for attachment to the helicopter skid tubes that extend longitudinally beneath the helicopter fuselage. The platform includes a lateral portion adapted to support a lineman working on high voltage power lines.
High voltage power lines, particularly the EHV (Extremely High Voltage) power lines, generate substantial electrical fields that make repair work extremely difficult. Various methods have been devised for protecting a lineman working on such power lines. For example, one technique, known as the bare hand method, requires that the lineman be surrounded by a Farady cage, which is electrically connected to the power line so that effectively there is no potential difference between the lineman and the power line. The Faraday cage may comprise an electrically conductive suit that the lineman wears and couples directly to the line. The lineman typically is positioned adjacent to the power line by means of a bucket truck, wherein a ground-supported truck elevates a bucket, holding a lineman, adjacent to the power line. The bucket must be insulated from the ground. The bucket is electrically connected to the power line so that no potential difference exists. Such technique has inherent dangers should the insulation between the bucket truck and the ground be incomplete or defective.
A further difficulty in working on power lines of the EHV type is that frequently repairs are required in remote areas that are inaccessible to land vehicles, such as the above-described bucket trucks. In such cases, the electrical power must be turned off, which is economically disadvantageous and operationally undesirable. Alternatively, the lineman uses long insulated poles, with tools attached at the pole end, to make the necessary repairs. Such technique is cumbersome.
Thus, a need exists for an apparatus and method for working on EHV-type power lines, or other high-voltage power lines, that is quick and economical and yet completely safe for the lineman. As will be described hereinbelow, the present invention provides for an apparatus and method of supporting a lineman from a hovering helicopter, wherein the lineman stands, sits or lies on an easily detachable work platform to perform the necessary work.
Prior art cargo carriers or baskets attached to helicopters are known. However, such attachments are not generally suitable for supporting a lineman from a hovering helicopter to enable him to work on high voltage power lines.